Development of a Compact Electrical Impedance Measurement Circuit for Protein Detection Two-electrode Impedance Micro-sensor

Abstract

Development of compact and low-cost electronic circuits in the biosensor field is an essential demand. Especially, the design of noise reduction sections plays an important role in the measurement of small biosensing signals. This study develops an electrical impedance measurement circuit board to apply in the protein pre-concentration and detection microfluidic chips with integrated two-electrode impedance micro-sensor. A lock-in amplifier is applied in the circuit board to measure the impedance profile in the frequency range 10–200 kHz. An investigation on several ratios of signal to noise (SNRs) is conducted to indicate the ability of the proposed design in eliminating noise signals. Subsequently, a total impedance and series capacitance-based analysis approach from the recorded impedance data is demonstrated to be suitable for this protein chip in the frequencies range from 10 to 200 kHz. The obtained results enable a potential method in point-of-care diagnostic applications.